Income-related inequities in cancer burden and patient-level years of life lost across age groups in South Korea

In this study, we aimed to examine the inequalities in the burden of cancer in Korea by income level and age group in 2020, 2021 and to elucidate the relevant national-level and individual-level trends. We used cause-of-death and life table data from the National Health Insurance Service and Statistics Korea for national-level analysis. The disability-adjusted life-year (DALY) calculation framework from the Korean National Burden of Disease Study was also used. DALYs were calculated using an incidence-based approach. For individual-level analysis, a generalised gamma linear model with a log link was used to calculate adjusted mean years of life lost (YLLs), using the Cancer Public Library Database. Adjusted mean YLLs were estimated by age group, income level, and SEER stage at cancer diagnosis. In both national- and individual-level analyses, individuals aged < 65 years were defined as non-older adults, while those aged ≥ 65 years were termed older adults. Total DALYs varied by cancer type, age, and income level at national-level analysis. Among the 15 cancers with the highest disease burden, non-older adults exhibited highly variable trends across income levels, whereas older adults demonstrated relatively stable patterns. As the income level increased, the proportion of DALYs attributed to YLLs demonstrated a decreasing trend. After adjusting for covariates in the individual-level analysis, the high-income group generally exhibited fewer YLLs compared to the low- and middle-income groups. We observed a decline in health equity across various parameters according to income levels. The differential disease burden and premature mortality patterns according to income level highlight the need for more detailed national cancer management policies, as well as the need for a policy design that takes age group into account.